What is the meaning of the
Stackexchange 404 image
"No pandas here" ? I google it but I couldn't find anything.
It just means there are no pandas here, and you have to look over there → to find them. Assuming you're looking for pandas.
Notice any themes? Feel free to try this on other public SE sites (that is, ones with a unique design) and see what you discover.
(Apparently we don't need a captcha on SE.com proper, so there's one page 'missing' in the theming there.)